The objective of this project is to develop and conduct a cancer epidemiology program designed to make efficient use of the military-veteran population, utilizing medical, demographic and environmental observations made at entry and during military service, and the subsequent medical history of veterals ascertained through facilities of the Veterans Administration supplemented by mortality data. The Field Studies and Statistics Program is concerned with studies to identify and clarify each etiologic factor in cancer. Work will include a study of Hodgkin's Disease, childhood cancer as it relates to prenatal x-ray, and follow-up of World War II Veterans with certain conditions possibly related to cancer (splenectomy, allergy, orchidopexy, nephrectomy, and alcoholism).